CRISPR-directed mitotic recombination enables genetic mapping without crosses

Narrowing down genetic loci of interest Often it can be difficult to identify a gene or genetic region that underlies a specific trait. Traditional mapping relies on naturally occurring recombination events but can be limited in resolution by the natural recombination frequency. Sadhu et al. used CRISPR technology to more easily map genomic sites of interest in yeast. The method systematically introduces local recombination events, allowing for the fine mapping of trait variants. They used their method to identify the causative mutation responsible for altered manganese sensitivity in yeast. Science , this issue p. 1113